Wall board



A ril 16, 1929. G, Q TT 1,709,475

WALLBOAR D Filed NOV. 9, 1928 INVENTOK 5 at 5 Gilberfflfloyy fff 7 9 m AH15 TORNEY Patented Apr. 16, 1929.

UNITED STATES GILBERT A. HOGGATT, OF KENMORE, NEW

PATENT OFFICE.

YORK, ASSIGNOB TO CERTAIN-TEED PROD UCTS CORPORATIC NZ OF NEXV YORK, N.Y., A CORPORATION OF MARYLAND.

WALL

Application filed November This invention relatcsto the elimination ofthe wavy and irregular edges often present in the paper goig into themanufacture of plaster wallhoard. The object of this invention is toeliminate these wavy edges and to secure a feeding lof'fla't' wallboardpaper into the wallboard machine.

Vallboard paper is dried to about 4%; moisture content at the paper milland it is wound into rolls 40" to in diameter and shipped to thewallboard plants. \Vhen exposed to the air this paperwill gradually takeup moisture along the edges or butts of the rolls in varying amountsdepending upon the temperature and relative humidity of the air.Normally itwill contain from about 5 to 8'}: moisture after exposure forany appreciable time. 'l.l1e.nio1sture from the air gradually penetratesthe exposed edges or butts of the roll for a distance of 2" t0 6" infrom the edge of the sheet. The edges of this pa per-having absorbedmoisture, expand, ar d in running rolls of paper which have been exposedto atn'iospheric conditions into the wallboard machine it is found thatthe edges so saturated and expanded, curl up, with the result that theedges are wavy. If these waves are not eliminated before the paperpasses through the forming rolls they will quite often remain in thesheet until the gypsum core has'setor hardened and the finished boardwill then have a wavy or irregular edge which is very undesirable.

To climi nate these wavy edges I have found it practical to installheating apparatus dircctly beneath the edges of the sheets as they ointo the plasterboard machine. The heating ammratus may be of anyconvenient or practicable kind and I do not wish to be limited to thespecific form of heater which is herein described as illustrative of myimproved method and apparatus.

In the accompanying drawings Figure 1 represents a side elevation of apart .of the ordinary plasterboard machine.

Figure 2 is a perspective view 0f.an illustrative example ot-a heatingunit.

Figure 3 is a bottom view of a plasterboard sheet passing over a pair ofheaters constructed in accordance with my invention.

Figure 4 is an end view of the plasterboard sheet shown in Figure 3.

In Figure 1. and 2 designate rolls of wallboard paper as they are set upin the plaster- BOARD.

9, 1928. Serial NO. 318,132.

board machine. 3 represents a guiding roll.

ft and 5 are the ordinary foi'ining rolls used In plasterboardmanufacture. ll) indicates plaster composition which is fed in betweenthe two sheets. 6 represent. the plasterboard sheet as it is fed intothe machine. 8 represents a plate of metal, preferably brass. to -'whicha metal angle bar, 9, is attached. The bar 9. may be attached to aconvenient support in order to -fix the plate, 8, into proper positionbeneath the edge of the plasterboard sheet. I'employ two bar and plateconstructions for each sheet, one under each edge. 7

represents the ordinary type of ele tric spa e heater which has beenfound satisfactory in the practice of this invention. A suitable numberof these heaters are attached to each plate.

As the plasterboard sheets are led toward the forming rolls the edgesthereof are dried 'by virtue of the heat supplied directly be- .neaththem through plates 8. It has been found convenient to heat these platesby the common electric space heater, although [do not wish to lilnitllIYSClfl'U the use of this particular heater as a means of practicingmy invention. The electric heaters are convenient because the heat mayhe controllcdby means of switches which allow one, two or three heatersto be energized. The electric heaters occupy a vcry-small'sparc and havebeen found quite satisfactory in the practice of this invention.

It can be seen that as the wallboard paper passes over these heaters themoisture content along the edges is decreased by virtue of the fact thatthc'moisture present in the edges is vaporized anddriven oft. Properregulation of the heatapplied in the plates will dry the edges to thesame degree of dryness pres- 4 cut in the sheet as it comes from thepaper mill. T

edge of wallboard comprising drying the 's the sheet is fed into theplaster board n. thine with a uniform morsture'conedges of the papersheets as they are fed into the wallboard machine until the moisturecontent of the sheets is uniform.

3. The method of reducing the moisture content in the edges of awallhoard-sheet com rising heating said edges as the sheet is fed intothe machine until the moisture content of the sheets is uniform. v

4. In combination with a wallboard machine, heating units positionedunder the edges of the \vnllhonrd. sheet as it is fed into the machine.7

5. In combination with a. wellboard inachine, heaters applieddirectlyunderneath the edges of the wallhoard heetes it is fed into the machine.

6. In combination with a. wallboard machine heaters applied directlybeneath the edges of the wallboard sheet as it fed touniform toeliminate wavy edges in the fin- 1 ward the tormingrolls, whereby thewavy edges due to excessive moisture in saidsheet are eliminated.

7. In combination with \vallboard'apparatus, heaters positioned beneaththe edges of thc-wallhoard sheet as it is fed from the feed rolls to theforming rolls whereby the moisture content in the wailooard sheet ismade ished product. I I

i 8. Ina Wellboerd niach1ne,in combination, feed rolls for feeding the.cover sheets into I the machine, forming rolls for forming the wallhosrdelements into a sheet of wallboard. and heaters positioned between saidfeed and forming rolls whereby the moisturecontent in the cover sheetsis made uniform.

9. In a wallhos-rd machine, in combination, feed rolls for feeding thecover sheets into the machine, forming rolls for forniin the wait boardelements into a sheet of wall o heaters positioned between said feed ae-l forming rolls whereby the wav edges in the finished product areeliminated 10. In a wallboard machine, in comuiz a tion, feed rolls forfeeding thecover shots into the machine, forming rolls for form? thewallboard elements into a sheetof .we'll board, and heaters positionedbetween said feed and forming rolls whereby wavy edges in the coversheets, due to an uneven moisture content thereof, are eliminated;

, 11. In a wallboard machine, in combine--- tion, feed rolls for feedingthe cover sheets in 0 the machine, forming rolls for forming thewallboard elements into a sheet of wali board, and heaters positionedbetween-said. feed and forming rolls whereby excess moisture content inthe edges of the cover sheets is eliminated andtheyare straightened before running through the forming rolls. 12. In a wallboard machine, incombination, feed rolls, forming rolls and heaters positioned betweenthe two to drv the cover sheets uniformly.

13. In a wallboard machine, in combination, feed rolls, forming rollsand heaters positioned between said feed and forming; rolls to remove,by drying, the waves in tlic edges of the wallhoard sheets.

' 14. In a wallboard machine, in oombination, feed rolls, forming, rollsand heaters poe sitioned between said feed and formingrolls whereby allportions of the wallboard sheet are reduced to a uniform moisturecontent.

In testimony whereof Iafiix my signature.

GILBERT A. HOGGAT'I ard, and

